Touch screens have been incorporated into many electronic devices. For example, in some applications, a touch screen is combined with a display device, such as a liquid crystal display (LCD), to form a user interface for a portable electronic device. A touch screen may respond to a user's touch and convey information of the user's touch to a control circuit of the portable device. In other applications, a touch pad is often part of a user interface for a device, such as a personal computer, to replace a separate mouse for user interaction with an onscreen image.
A touch screen device may implement a capacitive touch-sensitive matrix and capacitance measurements may be performed to detect a touch event by way of a finger or a stylus. For example, comparison of capacitance measurements data with no-touch data is often carried out for touch detection.